1. Technical Field
This disclosure relates generally to magnetic devices that write on magnetic media using perpendicular magnetic fields in the recording process. In particular it relates to a pole design that minimizes writing on regions of the medium that are adjacent to the intended track.
2. Description of the Related Art
The track pitch density in disks used in magnetic recording in a hard disk drive (HDD) is basically limited by adjacent track interference (ATI) during the writing process. The cause of ATI is stray fields from the main write pole or from the side shields that surround the main pole on its lateral sides. Although these side shields are intended to confine the fields for improved resolution, it is precisely these shields that contribute to unwanted writing on either side of the intended track and adversely affect the accuracy of the recorded information that is already there. In order to minimize the effects of unwanted recording on adjacent tracks and thereby interfering with what is already recorded there, it is necessary to eliminate these stray side fields to as great a degree as possible. The present disclosure is intended to improve ATI performance by suppressing these stray fields from the main pole and its side shields while not degrading the on-track performance of the writer.
Although the prior art indicates that many attempts have been made to address this important problem, with U.S. Pat. No. 8,351,154 to Etoh et al., U.S. Pat. No. 8,094,419 to Guan and U.S. Pat. No. 7,616,403 to Ho et al. being cited as only three recent examples, none of the teachings in these patents have taken the approach of this disclosure or have achieved the same degree of success.